The present invention relates to a circuit arrangement for generating an intermediate level potential between the maximum and minimum level potentials necessary to dynamically drive the display device.
A recent design tedency of diverse digital electronic apparatuses as typified by an electronic desk-top calculator is to miniturize the apparatus size and to reduce the power consumption of the apparatuses, by using integrated circuits comprising p- or n-channel insulated gate field effect transistors (IGFET or MOST) and a liquid crystal display device.
Because of chemical characteristic of the liquid crystal, the AC voltage driving system is preferable in order to elongate the life of the liquid crystal display device. When the dynamic drive or scanning drive system is employed, it is necessary to prebias the liquid crystal display segments at the intermediate potential level between the maximum and minimum potential levels which are displaying levels, since the response of the liquid crystal display device is slower than those of other type display devices. To provide an intermediate level potential or potentials a prior art LC display device uses a resistive voltage dividing circuit through which current always flows. Therefore, power dissipation of the dividing circuit or display device becomes necessarily large. Application of large resistance value elements to the dividing circuit so as to reduce the power dissipation is not desirable since the liquid crystal is capacitive.